1. Field of the Invention
The present invention relates to a reciprocating power tool such as a reciprocating saw and more particularly, to a technique for reducing vibration in cutting a workpiece and a cutting technique when the reciprocating power tool is in operation.
2. Description of the Related Art
Japanese non-examined laid-open Patent Publication No. 2001-9632 (hereinafter referred to as “D1” discloses an electric reciprocating saw as an example of a reciprocating power tool. The known reciprocating saw includes a motion converting mechanism for causing a slider to reciprocate in the longitudinal direction. A counter weight is provided in the motion converting mechanism. When the slider reciprocates, the counter weight reciprocates in a direction opposite to the reciprocating direction of the slider, with a 180° phase shift with respect to the slider. As a result vibration of the reciprocating saw caused by the reciprocating movement of the slider can be reduced.
Further, Japanese non-examined laid-open Patent Publication No. 06-79701 (hereinafter referred to as “D2”) discloses an electric reciprocating saw having a first motion converting mechanism for converting the rotating output of a motor into reciprocating linear motion in the longitudinal direction of the slider and a second motion converting mechanism for converting the rotating output of the motor into swinging motion in the vertical direction of the slider. In the reciprocating saw having such a construction, the tool bit or the blade supported by the slider not only linearly reciprocates in the longitudinal direction, but swings in the vertical direction, whereby the cutting efficiency can be increased.
In the reciprocating saw as disclosed in D1, because the counter weight is additionally provided for vibration reduction in the motion converting mechanism, the weight of the reciprocating saw itself is increased by the weight of the counter weight. Therefore, further improvement is desired in this respect. On the other hand, in the reciprocating saw disclosed in D2, the actuating mechanism for the blade includes the first motion converting mechanism for causing the blade to linearly reciprocate and the second motion converting mechanism for causing the blade to swing in the vertical direction. Therefore, the actuating mechanism is complicated in structure, the weight of the entire saw is increased, and the size of the entire housing for housing these mechanisms is increased. Therefore, further improvement is also desired in this respect.